BEIJERSBERGEN J & BEIJERSBERGEN, R (1976) Some data on the breeding birds of Hompelvoet in connection with the enclosure of the Brouwershavense Gat 1968 - 1975. LIMOSA 49 (3): 123-130.

Hompelvoet is a triangular sandbar, situated in the western part of the Grevelingen, between the islands Goeree-Overflakkee and Schouwen-Duiveland. After enclosure of the Brouwershavense Gat, as a part of the Delta Works, in May 1971, 1000 acres of the sandbar emerged from the sea since the water is no longer tidal. As a consequence of the absence of the tide, Hompelvoet has acquired increased value as a breeding place for birds like the Kentish Plover, Ringed Plover and Avocet, whosenatlJral habitat it is. For species that breed in colonies on the ground, like the Little Tern and Sandwich Tern, Hompelvoet has even become the most important breeding place in the South-West Netherlands (Table I). Sinc.e the absence of the tide the breeding of the Black-headed Gulls and Sandwich Terns have not only increased in number, but the nesting has also started earlier in the season. The Common Tern has increased far less in number after the enclosure and no acceleration of the breeding season has occurred (Table 2, 3). There may be more than one reason for an earlier start of thenesting period. 1. A larger supply of food for the parent birds at an earlier time than normal because of the warmer winters. In the last few years some Sandwich Terns have stayed inthe Brouwershavense Gat during the winter (OuweneelI975). 2. The absence of the tide. The vegetation season starts earlier. Before the enclosure Hompelvoet was visited by breeding birds whose clutches had been lost elsewhere and who nested here for the second time, later in the season (Rooth and Morzer Bruijns 1959). From recent investigations it has become evident that especially birds starting their very first breeding season, will settle in new territories. They also start nesting later than the older birds (Coulson and White, 1958, 1960, Nehls 1969). The last coupleof years the breeding colonies on Hompelvoet have acquired a more permanent character and they no longer consist only of first year breeding birds. The revival of the Dutch populations, so that larger groups of terns are present at the gathering spots early in Spring. These larger numbers may make succesfull settling at an earlier time in Spring possible (reciprocal influence). The Black-headed Gull as a breeding bird exists in large numbers in the Netherlands and has strongly increased in number on Hompelvoet. This means that they may become an increasing attraction to the terns. Black-headed Gull Chroicocephalus ridibundus = Larus ridibundus Common Tern Sterna hirundo Sandwich Tern Thalasseus sandvicensis = Sterna sandvicensis Mallard Anas platyrhynchos Common Moorhen Gallinula chloropus Eurasian Oystercatcher Haematopus ostralegus Northern Lapwing Vanellus vanellus Common Ringed Plover Charadrius hiaticula Kentish Plover Charadrius alexandrinus Common Redshank Tringa totanus Pied Avocet Recurvirostra avosetta Common Gull Larus canus canus Black-headed Gull Chroicocephalus ridibundus = Larus ridibundus Common Tern Sterna hirundo Arctic Tern Sterna paradisaea = Sterna macrura Little Tern Sternula albifrons = Sterna albifrons Eurasian Skylark Alauda arvensis Meadow Pipit Anthus pratensis White Wagtail Motacilla alba Blue-headed Wagtail Motacilla flava Common Linnet Carduelis cannabina

[free pdf] [dutch summary]